1. Field of the Invention
The present invention relates to a golf club set consisting of a plurality of golf clubs.
2. Description of the Prior Art
In case of the wood clubs among a conventional golf club set consisting of wood clubs or woods and iron ones or irons, an axis X passing through the center of the shaft 1 thereof and a line X' passing through the hitting spot H and parallel to the axis X lie in a plane squarely facing the golfer as shown in FIG. 1. Assume here that the distance between X and X' in the above-mentioned plane is y (taking as positive the relation between the axis X and the hitting spot H when the axis X is in front of the hitting spot H and the relation as negative when the axis X is behind the hitting spot H. (The "hitting spot H" is the point of contact between the hitting face of the club and a golf ball when the sole of the club is squarely set on the playing surface.) The hitting spot H on the club face lies in front of the axis in the direction of the ball's flight and the distance y between X and X' is within a range of about -5 to -20 mm for the woods, and is within a range of about -1 to 5 mm for the irons, as indicated in FIG. 2. For example, for a golf club set consisting of 12 clubs in total, i.e. wood Nos. 1, 3, 4, 5, iron Nos. 3.about.9, and pitching wedge, the values of y of the clubs are distributed as indicated by the graph in FIG. 3. For a conventional golf club set the difference in y between a large number wood club, e.g. W 5, and a small number iron club, e.g. I 3, exceeds 10 mm.
For a conventional golf club set there exists a difference in y exceeding 10 mm even between a high number club among the wood clubs, e.g. wood No. 5 (W 5) and a small number club among the iron clubs, e.g. iron No. 3 (I 3) and the golfer is disoriented, when he changes the club which he uses from the wood club to the iron one. Therefore, it is difficult to properly use them and he is susceptible to a missed shot.
For a conventional wood club, whose head is made of persimmon, the value of y is within a range from -10 to -20 mm, so that the ball hit by any average golfer with a wood is likely to result in a slice. This is due to the fact that since he swings trying to hit the ball B at a spot of the club head which lies on the shaft 1, namely, on or near the extension of the grip, the ball B is hit by the club head earlier than he thinks because the hitting spot H lies in front of the shaft 1. The ball is impacted by the club head before he has completely directed the club face toward the target. That is, the ball is hit with the club face open. At this time, a slicing rotation is imported to the ball, even if the head 2 is swung along the line of ball's flight Z. Also during his swing, his wrist rotates (causing the rotation of the head around the shaft 1 and rolling of the head) and the velocity v of the hitting spot H resulting from the wrist rotation acts to impart a slicing rotation to the ball B as shown in FIG. 4. This velocity v of the hitting spot H is determined from the equation v=r.omega. (where r is a distance from the center of the rolling to the hitting spot H and .omega. is an angular velocity of rotation). If he tries to hit ball B with the club face somewhat closed on purpose as shown in FIG. 5 in order to correct the slice, the ball thus hit will result in a hook. However, this hitting technique cannot easily be attained by the average golfer. The professional and skillful golfers have a full understanding of the differences between the woods and irons and use the clubs effectively. The majority of the average or beginner golfers use both the woods and irons in a same manner. The ball hit by the average golfer with a wood is apt to result in a slice. Further, the average golfer hardly handles long irons (I 3.about.I 4) and for a distance with respect to which the ball hit by the wood club No. 3 or 4 flies too far, almost all the golfers using I 3 or I 4 fail to make the ball reach the pin. For the average golfer there is a gap between the wood clubs Nos. 3 and 4 and the long irons, which is rarely overcome.